'use strict'

const DuplexStream = require('readable-stream').Duplex
const inherits = require('inherits')
const BufferList = require('./BufferList')

function BufferListStream (callback) {
  if (!(this instanceof BufferListStream)) {
    return new BufferListStream(callback)
  }

  if (typeof callback === 'function') {
    this._callback = callback

    const piper = function piper (err) {
      if (this._callback) {
        this._callback(err)
        this._callback = null
      }
    }.bind(this)

    this.on('pipe', function onPipe (src) {
      src.on('error', piper)
    })
    this.on('unpipe', function onUnpipe (src) {
      src.removeListener('error', piper)
    })

    callback = null
  }

  BufferList._init.call(this, callback)
  DuplexStream.call(this)
}

inherits(BufferListStream, DuplexStream)
Object.assign(BufferListStream.prototype, BufferList.prototype)

BufferListStream.prototype._new = function _new (callback) {
  return new BufferListStream(callback)
}

BufferListStream.prototype._write = function _write (buf, encoding, callback) {
  this._appendBuffer(buf)

  if (typeof callback === 'function') {
    callback()
  }
}

BufferListStream.prototype._read = function _read (size) {
  if (!this.length) {
    return this.push(null)
  }

  size = Math.min(size, this.length)
  this.push(this.slice(0, size))
  this.consume(size)
}

BufferListStream.prototype.end = function end (chunk) {
  DuplexStream.prototype.end.call(this, chunk)

  if (this._callback) {
    this._callback(null, this.slice())
    this._callback = null
  }
}

BufferListStream.prototype._destroy = function _destroy (err, cb) {
  this._bufs.length = 0
  this.length = 0
  cb(err)
}

BufferListStream.prototype._isBufferList = function _isBufferList (b) {
  return b instanceof BufferListStream || b instanceof BufferList || BufferListStream.isBufferList(b)
}

BufferListStream.isBufferList = BufferList.isBufferList

module.exports = BufferListStream
module.exports.BufferListStream = BufferListStream
module.exports.BufferList = BufferList